1. Field of the Invention
The present invention relates to a multilayer microelectronic circuit with a trimmable capacitor, which is adjustable in capacitance over a wide range.
2. Description of the Prior Art
A technique for adjusting the capacitance of a capacitor in a multilayer microelectronic circuit is disclosed in JP 3-71710. In this Japanese patent publication, a multilayer microelectronic circuit is disclosed as a resonator including a pair of electrodes with a dielectric layer being interposed therebetween. On one side of the pair of electrodes is disposed a surface dielectric layer on which a trimmable electrode is mounted. Fine adjustment of the resonance frequency of the resonator, which resonance frequency may deviate from a target value due to manufacturing error, etc., is attained by trimming the trimmable electrode.
The prior art technique, however, is only for fine adjustment of the resonance frequency which may deviate from a target value due to manufacturing error, etc. and does not enable variations or modifications of the resonance frequency of the resonator once manufactured. Thus, for different resonance frequencies, resonators different in capacitance are necessitated. With the prior art technique, it is therefore necessitated to design and manufacture resonators for every frequencies, resulting in a high cost of the resonator.
Further, the prior art technique is only for adjustment of a resonance frequency and cannot regulate the other control factors than the resonance frequency, such as the capacitance for determining a band width of an input/output filter. In other words, the adjustable range of the capacitance of the capacitor in the prior art multilayer microelectronic circuit is small.